A scroll compressor is provided with a capacity modulation control, including a solenoid valve which can be moved to selectively move the compressor between a full capacity and a reduced capacity position, and wherein the solenoid valve is mounted outside of a compressor shell.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a pair of generally spiral wraps interfit to define compression chambers. One of the wraps is caused to orbit relative to the other, and as the two move, the size of the compression chamber is reduced, thereby compressing an entrapped refrigerant.
Under certain conditions, the capacity, or amount of refrigerant compressed by the compressor, may be desirably reduced. As an example, if the compressor is incorporated into an air conditioning system, and the cooling load is low, then it is more energy efficient to compress less refrigerant.
Various ways are known for reducing the capacity, including moving a valve to selectively open a passage to allow refrigerant to move from a partially compressed location back to a suction. However, providing power to these valves has been somewhat challenging.
In particular, when electric valves such as solenoid valves have been utilized to provide capacity control within a scroll compressor, they have been mounted within a hermetically sealed compressor shell. Thus, the valves are exposed to the refrigerant circulating within the shell. The terminals that supply electric power to the valves must then have a hermetically sealed connection. In addition, since the valve is within the shell, it is somewhat difficult to cool the valve, or replace the valve.
It has been proposed to mount such a valve entire outside of a shell. However, this requires communicating flow passages, which are outside of the shell also, and thus leads to some plumbing challenges.